I might be able to help. Firstly, the price is so low because the "heavyweight wool" is not the same as a Scottish Worsted 16 oz. wool cloth. I'm pretty sure the wool the SWKs are made from are woven in the Middle East. I know the kilts are constructed there. The price is also low because the kilts are mass produced, and are not hand sewn garments (like the CCK Maple Leaf and Matt Newsome hand sewn PSD tartans you mentioned.) Having once owned a SWK heavyweight and still owning a Matt Newsome made from Lochcarron Strome, I can tell you there is no comparison. That's not say the SWK heavyweight is "no good." But, the price difference is certainly justified.

Pleating to the sett means the full tartan pattern appears across the pleats. Pleating to the stripe is where the pleats are all set to the same recurring stripe. If that makes any sense...